Config new UDR7 into existing home network

I have long time existing home network with router/FW GW 192.168.1.1. I cannot put into bridge mode. I have another NG wifi router that serves a small segment of the /24. I also have a UAP-AC-PRO for another few devices in the same /24. I want to add the UDR7 to the same /24 and tell the UDR7 WAN port to use the 192.168.1.1 GW to hit the internet, use the UDR7 wifi and eventually migrate/replace the existing router/FW/GW with the UDR7. Does not seem right that the UDR7 cannot be configured to do this but it seems it would have to use another LAN address. Can anyone suggest if this is possible? I would like to see how the UDR7 performs before I disrupt my whole network.

I don’t really think there is a way to configure the UDR to do that. It is designed to act as the gateway in the network, not as a standalone WiFI.